John Gill emphasizes the spiritual peril of hatred towards others, explaining that those who harbor such feelings are enveloped in darkness and are unaware of their spiritual blindness. He illustrates how this darkness leads to a lack of discernment between good and evil, causing individuals to stumble through life without recognizing the dangers that lie ahead. Gill warns that this state of ignorance is a result of sin and the influence of Satan, which blinds the heart and mind, preventing one from understanding the path to peace and salvation through Christ.

Ver. 11. But he that hateth his brother is in darkness,.... As is before expressed in 1Jo 2:9, to which is added, and walketh in darkness; he goes on in it, and takes delight in it, as dangerous and uncomfortable as it is: and knoweth not whither he goeth; he cannot discern between good and evil; he puts darkness for light, and light for darkness; he sees not what is before him, nor what stumblingblocks lie in the way; he is not aware of the snares, pits, and traps he is in danger of falling into; nor does he know and consider what these paths of darkness, of sin, and ignorance, and infidelity, lead unto, even unto utter darkness, where is weeping, wailing, and gnashing of teeth: and the reason is, because that darkness hath blinded his eyes; either Satan, the god of this world, who blinds the minds of them that believe not, and who is darkness itself, and the cause of darkness in himself and in others, and one of whose names this was with the Jews {e}; See Gill on "Lu 22:53"; or that natural darkness which sin has brought upon the understanding, and has blinded the eyes of it, called the blindness of the heart, Eph 4:18, so that a man under the power of it is ignorant of himself, and knows not that he is blind and miserable; is a stranger to the way of peace, and life by Christ, and knows not what he is about, and where he is, or whither he is going, and what his end will be. {e} Yalkut Simconi, par. 2. fol. 44. 4.